The acid-catalyzed cleavage of an ether with HBr involves the following mechanism:1. Protonation of the ether oxygen: The ether oxygen atom acts as a Lewis base and donates a lone pair of electrons to the HBr, a strong acid. This protonation step generates an oxonium ion a positively charged oxygen atom .2. Nucleophilic attack by bromide ion: The bromide ion Br- generated from the dissociation of HBr acts as a nucleophile and attacks the carbon atom bonded to the oxonium ion. This step leads to the cleavage of the C-O bond and the formation of an alkyl bromide.3. Deprotonation: If the other alkyl group attached to the oxygen atom is not a tertiary alkyl group, the remaining alkyl group will be protonated by another HBr molecule, and the process will repeat, resulting in the formation of another alkyl bromide. If the remaining alkyl group is tertiary, it will directly form a tertiary alkyl bromide without the need for protonation.The reaction mechanism differentiates between primary, secondary, and tertiary ethers based on the stability of the carbocation intermediate formed during the nucleophilic attack. Tertiary carbocations are more stable than secondary carbocations, which are more stable than primary carbocations. Therefore, the reaction proceeds faster for tertiary ethers compared to secondary and primary ethers.Example:Consider the acid-catalyzed cleavage of diethyl ether CH3CH2-O-CH2CH3 with HBr:1. Protonation: CH3CH2-O-CH2CH3 + HBr CH3CH2-OH2+-CH2CH3 + Br-2. Nucleophilic attack: CH3CH2-OH2+-CH2CH3 + Br- CH3CH2Br + CH3CH2OH3. Deprotonation: CH3CH2OH + HBr CH3CH2Br + H2OOverall reaction: CH3CH2-O-CH2CH3 + 2 HBr 2 CH3CH2Br + H2OThe stereochemistry of the product formed depends on the stereochemistry of the starting ether. In the case of diethyl ether, which is an achiral molecule, the products formed ethyl bromide and water are also achiral. However, if the starting ether has chiral centers, the stereochemistry of the products will depend on the configuration of the chiral centers and the reaction mechanism. In general, the stereochemistry of the products formed in the acid-catalyzed cleavage of ethers with HBr is determined by the stereochemistry of the starting ether and the stability of the carbocation intermediates formed during the reaction.